Vibratory finishing machine

ABSTRACT

A vibratory finishing machine having an improved screen separating device and discharge mechanism for separating the finished parts from the polishing media at the conclusion of a finishing operation and for discharging the parts from the machine, and improved drive mechanism for imparting vibratory motion to the bowl of the finishing machine.

United States Patent Ferrara [54] VIBRATORY FINISHING MACHINE [72] Inventor: Achille K. Ferrara, 848 Westgate Drive, Addison, 111. 60101 22 Filed: Jan. 14, 1971 211 App1.No.: 106,503

[52] US. Cl ..5l/l63 -[5 1] Int. Cl. ..B24b 31/06 [58] Field of Search ..51/163; 241/175 [56] References Cited UNITED STATES PATENTS 3,268,177 8/1966 McKibben ..5l/163 X 3,429,560 2/1969 Huber ..51/l63 X 1 Sept. 26, 1972 Ferrara ..51/163 UX McKibben ..5l/163 Primary Examiner-Harold D. Whitehead Attorney-Gary, Parker, .luettner, Pigott & Cullinan 5 7] ABSTRACT A vibratory finishing machine having an improved screen separating device and discharge mechanism for separating the finished parts from the polishing media at the conclusion of a finishing operation and for discharging the parts fromthe machine, and improved drive mechanism for imparting vibratory motion to the bowl of the finishing machine.

16 Claims, 3 Drawing Figures 1 VIBRATORY FINISHING MACHINE BRIEF SUMMARY OF THE INVENTION The present invention relates to a finishing machine including a vibratory bowl in which are disposed parts to be finished and polishingmedia whereby the parts and media are mixed together and vibrated in the bowl for the purpose of polishing deburring or otherwise finishing the parts. Such parts may comprise a wide variety of metal castings and other articles of manufacture, and the polishing media may for example comprise any suitable abrasive agent such as granite, aluminum oxide, sand, chipped marble, steel balls, corn cobs, etc. When the parts and media are vibrated together in the bowl of the finishing machine, the resultant rubbing action causes the parts to be polished. It is also common practice to wet the finishing media with a detergent solution for the purpose of washing away fine abrasive particles and the like.

At the completion of a polishing operation, it is necessary to separate the finished parts from the media, and various procedures are known for separating the parts from the media and removing such parts from the finishing machine while permitting the media to remain in the vibratory bowl for subsequent finishing operations.

One of the objects of the present invention is to provide a vibratory finishing machine where the drive motor is mounted independently of the vibratory bowl and where cordless belt means is utilized to provide an operative connection between the motor and a vertical drive shaft carried by the bowl assembly. Such an arrangement permits the use of a conventional variable speed drive pulley to adjust the drive speed. Moreover, it substantially reduces wear and tear on the motor as compared with machines where the motor is mounted directly on the vibratory bowl assembly, and it permits the motor to be located away from the heat, humidity and contamination present in the immediate area of the vibratory bowl.

Anothr object of the invention is to provide an improved vibratory drive shaft and counterweight assembly for a vibratory finishing machine which produces a balanced drive system and is therefore well adapted to be driven by means of an endless drive belt in the manner described hereinabove. Conventional vibratory finishing machines produce a vibratory movement of the vertical center shaft which is too violent to permit use of a drive belt arrangement thereby necessitating that the drive motor be mounted directly on the bowl assembly.

A further object of the invention is to provide a vibratory finishing machine wherein the media action is such that as it moves toward the center of the bowl it tends to be sucked downwardly and outwardly without any substantial need to be repelled by the inner wall of the bowl, and to provide a vibratory bowl wherein the inner wall of the bowl is of substantially reduced height relative to the outer wall thereof.

Still another object of the invention is to provide a vibratory finishing machine which is substantially insensitive to the weight of the media used so that the operation will be substantially the same whether the bowl contains a heavy media such as steel balls or a very light media such as corn cobs or the like.

A further one of my objects is to provide a vibratory finishing machine having improved screening means for separating the parts from the media at the conclusion of a finishing operation.

A still further object is to provide a machine as lastabove-mentioned having improved ejection means whereby finished parts are ejected down through a chute located at the center of the vibratory bowl.

Certain of the features of the present invention comprise an improvement over the inventions disclosed and claimed in my US. Pats. Nos. 3,037,327 and 3,470,754 which are assigned to the assignee of the present invention.

The foregoing and other objects and advantages of the invention will be apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a vibratory finishing machine constructed in accordancewith the present invention;

FIG. 2 is a top plan view of the machine of FIG. 1; and

FIG. 3 is a vertical sectional view taken substantially along the line 3-3 of FIG. 2.

Now, in order to acquaint those skilled in the art with the manner of making and using my invention, I shall describe, in conjunction with the accompanying drawings, a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, there is shown a stationary base 10 on which a mounting plate 12 is supported by a plurality of circumferentially spaced vertical compression springs 14. FIG. 3 shows the manner in which each of the springs 14 is located between the underside of the mounting plate 12 and a horizontal ledge portion 16 at the upper end of the base 10. The number and size of the vertical compression springs 14 will normally vary depending upon the size of the finishing machine. For example, in smaller size machines, six such springs 14 may be sufficient, whereas in larger machines as many as sixteen or more springs may be utilized. It has also been found that while it is desirable to locate the several springs 14 in circular fashion so that each is on the same radius relative to the center of the bowl, it is not necessary that the springs be equally spaced from one another in all instances.

A vibratory bowl 18 is welded or otherwise fixedly secured to the top of the mounting plate 12 for the purpose of containing polishing media and parts to be finished. The bowl 18 is annular in shape as viewed in top plan in FIG. 2. As viewed in vertical section in FIG. 3, the wall of the bowl indicated generally at 20 comprises an arc of a circle. The radially outer portion of the circular arc is indicated at 22 and is hereafter referred-to as the outer wall of the bowl, whereas the inner portion of the circular arc is indicated at 24 and is hereafter referred to as the inner wall of the bowl. The letter C is used in FIG. 3 to designate the center point about which an arc is swung to develop the arcuate surface of the bowl wall 20 It is important to note that the outer wall 22 extends upwardly well above the height of the center point C and terminates in an upper edge portion 26, whereas the inner wall 24 terminates at an upper edge 28 which is approximately at the same height as the center point C. Due to the annular shape of the bowl 18, as seen in FIG. 2, the inner wall 24 taken in its entirety comprises a center post which as explained above is of a height approximately at the level of the center point C and well below the upper outer edge 26 of the bowl.

It will be noted that the inner bowl wall 24 is bent inwardly to form an annular flange 30, and the flange 30 defines a round opening 32 which is normally closed by a removable plug 34. A discharge chute 36 is welded or otherwise fixedly secured to the underside of the annular flange 30. As will be explained more fully later hereimat the completion of a finishing operation the finished parts are separated form the polishing media, and the plug 34 is removed, whereby the parts are ejected down through the opening 32 in the centerpost 24 and out through the discharge chute 36.

A screen assembly indicated generally at 38 is provided for the purpose of separating the finished parts from the polishing media at the conclusion of a finishing operation. The screen assembly 38 comprises an outer wall 40 and an inner wall 42 which are interconnected at their bottom portions by various cross members as shown for example at 44 and 46, the latter cross member also serving as an inclined entrance ramp. The outer wall 40 has one end 48 which extends approximately to the outer wall 22 of the bowl, and the wall 40 includes an arcuate portion 50 which ultimately terminates at an opposite end portion 52 adjacent one side of the centerpost 24. The inner wall 42 has one end 54 which is connected with the ramp 46, and its opposite end indicated at 56 terminates adjacent an opposite side of the centerpost 24. A substantially flat or coplanar screen 58 is cut to a shape as shown in FIG. 2 whereby it will fit between the outer and inner walls 40 and 42 of the screen assembly and thereby define a curved path leading from the entrance ramp 46 to the center of the bowl 18 where the opening 32 is formed in the center post 24. The screen assembly 38 includes a flat annular plate 60 which is welded or otherwise fixedly secured to the outer and inner walls 40 and 42 at the underside thereof. The annular plate 60 corresponds approximately in size to the annular flange 30 which forms the upper surface of the bowl center post' 24, and when the screen assembly 38 is in operative position, the annular plate 60 is disposed on top of the flange 30. A pair of oppositely disposed wedge plates 62 and 64 are welded to the top surface of the annular plate 60 in oppositely disposed relation. The wedge plates 62 and 64 are horizontally positioned in substantially coplanar relation, and arcuate slots 66 and 68 are formed therein respectively with the slot 66 having an enlarged end portion 70 and the slot 68 having an enlarged end portion 72. It should be understood that corresponding slots are also formed in the annular plate 60 Referring now to FIG. 3, it will be seen that a pair of oppositely disposed headed lock pins 74 and 76 are welded or otherwise fixed to the annular bowl flange 30. The headed pins 74 and 76 extend upwardly from the flange 30 so that the screen assembly 38 may be locked in position by locating the same with the annular ring plate 60 superimposed on the bowl flange 30 in such a manner that the headed lock pins project up through the enlarged end portions and 72 of the arcuate slots 66 and 68 formed in the wedge plates 62 and 64. Thereafter, the screen assembly may be rotated in a counterclockwise direction as viewed in FIG. 2 causing the pins 74 and 76 to be located in the narrow ends of the slots 66 and 68 thereby securing the screen assembly 38 to the top of the bowl center post 24. Moreover, the wedge plates 62 and 64 are preferably formed of varying thickness so that when the screen assembly is rotated in a counterclockwise direction as above-mentioned the thicker portions of the wedge plates are moved under the head portions of the lock pins 74 and 76 thereby tightly wedging the screen assembly in its operative position as shown in FIG. 2. It will of course be understood that by rotating the screen assembly 38in a clockwise direction as viewed in FIG. 2 and then lifting the same, the assembly may be readily removed from the bowl 18 of the vibratory finishing machine.

The screen 58 is also readily replaceable and this is a desirable feature for the reason that an operator will want to select a screen of a particular mesh depending upon the nature of the polishing media and parts to be separated. FIG. 2 shows a screen retainer plate 78 which is of a shape corresponding to that of the outer wall 40 and extends along the major portion of the length of the latter. The screen retainer plate 78 is disposed immediately inside the outer wall 40 and is positioned so as to overlie the outer edge portion of the screen 58 so as to retain the latter in position. A wing nut 80 cooperates with a threaded stud or the like 82 on the plate 78 to secure the latter in position. A second screen retainer plate 84 is secured to the inside of the inner wall 42 of the screen assembly by a wing nut 86, and the plate 84 overlies the inner edge portion of the screen 58 to retain the latter in position. It will be understood from the foregoing that by removing the screen retainer plates 78 and 84, it is a simple matter to remove the screen 58 and replace the same with another screen of a different mesh depending upon the nature of the polishing media and parts to be separated.

When the screen assembly 38 is mounted in operative position as shown in FIG. 2, it is desirable to attach the same to the rim of the bowl 18 in order to provide for a more rigid mounting. In the embodiment shown in FIG, 2, the outer wall 40 of the screen assembly includes a bracket 88 which carries a wing bolt 90 for attaching to the rim of the bowl 18. Additional connections to the bowl rim may be provided if desired to assure that the screen assembly is rigidly mounted when disposed in operative position. I

Reference is now made to FIG. 3 which discloses a vibratory drive mechanism for applying vibratory motion to the spring-mounted bowl 18. A drive shaft housing 92 is supported in depending relation from the mounting plate 12 by a plurality of support arms 94. It will thus be understood that the drive shaft housing 92 is a part of the assembly which includes the bowl l8 and which is supported from the base 10 by the springs 14. A vertical drive shaft 96 has an upper eccentric bushing 98 and a lower eccentric bushing 100 keyed or otherwise fixedly secured thereto, and the bushings 98 and 100 are journalled in bearings 102 and 104 which are carried by the drive shaft housing 92. Radial arms 106 and 108 are affixed respectively to the upper and lower ends of the drive shaft 96 for rotation therewith, and such radial arms carry weights 110 and 112 respectively at their outer ends.

A drive motor 114 is carried on a mounting plate 116 which is connected with the stationary base by a vertical pivot pin 118. The mounting plate 116 carries an adjustable screw 120 which engages against the side of the base 10 and controls the pivotal position of the mounting plate 116. A motor shaft 122 has a motor pulley 124 mounted thereon for rotating the drive shaft .96 by means of an endless drive belt 126 which is trained over a second pulley 128 mounted on the drive shaft 96. The motor pulley 124 comprises a conventional split pulley including an adjustable control screw 130 whereby adjustment of the screw 130 varies the spacing between the two halves of the pulley and thereby varies the effective diameter of the pulley for the purpose of adjusting the speed of the drive belt 126. The drive shaft pulley 128 is also preferably of the variable speed type comprising two pulley half sections spring-loaded toward one another whereby the spacing between such half-sections and thus the effective diameter of the pulley may be varied by varying the tension on the drive belt 126. It will thus be understood that dual adjustment of the speed of rotation of the drive shaft 96 is provided through adjustment of the screw 130 which varies the effective diameter of the pulley 124 and by adjustment of the screw 120 which varies the belt tension and thereby varies the effective diameter of the pulley 128.

FIG. 3 further shows an annular tube or spray pipe 132 which is mounted to the top outer edge of the bowl 18 for spraying a suitable liquid such as a detergent solution or the like on the polishing media. The bowl 18 further includes a liquid drain 134, and a removable door 136 for removing the polishing mediafro the bowl.

In operation, the bowl 18 is filled at least approximately to the height of the centerpost 24 with a selected polishing media such as chipped stone, and a plurality of parts to be finished are placed in the bowl with the polishing media. The motor 114 is started so as to bring the drive shaft 96 up to speed, and the speed is adjusted to a desired rate by the adjusting screw 130 and/or the adjusting screw 120. As the drive shaft 96 is being brought up to speed, it rotates about the centerline of the bearings 102 and 104 which is offset from the centerline of the drive shaft due to the eccentric bushings 98 and 100. However, as the shaft 96 is brought up to normal operating speed, e.g., in the range of 1,000 to 2,200 rpm, the shaft 96 and bushings 98 and 100 tend to rotate substantially about the axis of the shaft so that at normaloperating speed there is little or no oscillation of the shaft 96, whereas vibratory or oscillator motion is imparted to the bowl 118.

The nature of the oscillatory motion imparted to the bowl 18 is controlled in part by the upper and lower weights 110 and 112 which rotate with the shaft 96. The weights 110 and 112 are arranged so, as to be approximately opposite the heavier sides of the corresponding eccentric bushings 98 and 100, and they are preferably maintained only slightly out of vertical alignment with one another. For example, the weights are normally spaced apart by an amount less than 45, and

the preferred angle between them for many applications is approximately 5. The oscillatory motion imparted to the bowl 18 causes the media within the bowl together with the parts mixed therewith to move in a generally circular fashion as viewed in FIG. 3 down the inside bowl wall 24, outwardly and upwardly along the outer bowl wall 22 and then inwardly, while at the same time the media and parts move slowly around the annular bowl in a counterclockwise direction as viewed in FIG. 2. Consequently, the resultant motion of the media is that it follows a generally spiral path as it moves around the bowl in a counterclockwise direction as viewed in top plan in FIG. 2. The number of orbits through which the media moves in a 360 traverse around the bowl can be reduced by moving the upper and lower weights and 112 closer toward vertical alignment, and can be increased by spacing the weights further apart.

in the finishing machine of the present invention, the media and parts tend naturally to be sucked downwardly as they approach the inner bowl wall 24 with the result that there is no substantial impinging of the media and parts against the inner bowl wall, and for this reason it is possible in the instant finishing machine to provide an inner bowl wall or centerpost 24 of substantially reduced height relative to the outer bowl wall 22. Such a design has the advantage of affording an improved finishing action by reducing the impact between the parts to be finished and the walls of the bowl, and the reduces height of the centerpost permits the finishing of larger parts for a given size of bowl. During such a finishing operation, it will be understood that the screen assembly 38 is removed from the finishing machine, and the plug member 34 is positioned to close the opening 32 in the bowl centerpost 24.

When the finishing operation has been completed, the screen assembly 38 is mounted on the bowl 18 and the plug 34 is removed from the opening 32. With the screen assembly 38 in operative position, the media and parts as they move in spiral fashion in a counterclockwise direction around the bowl are automatically fed over the ramp 46 and onto the screen 58. The parts and media move along the screen guided where necessary by the outer and inner walls 40 and 42 of the screen assembly until the finished parts which are larger than the screen openings reach the centerpost 24 and fall through the opening 32 and down the discharge chute 36. The polishing media will fall down through the openings in the screen 58 prior to reaching the centerpost opening 32 and thus will remain in the bowl for use in subsequent finishing operations.

It is important to note that in accordance with the finishing machineof the present invention it is not necessary to use a spiral ramp or any special damming devices to elevate theparts and media for purposes of separating the same. As previously noted, the screen 58 is disposed approximately horizontally at a height approximately equal to that of the centerpoint C of the bowl as shown in FIG. 2 which also corresponds approximately with the height of the bowl centerpost 24. When the bowl 18 is substantially filled with parts and media and the bowl is oscillated as hereinabove described, the media and parts will move through a conventional spiral path with the result that they will move up over the ramp 46 and onto the screen 58 between the walls 40 and 42. The screen 58 is substantially coplanar, and while it is not necessary to position the screen at any substantial inclination from the horizontal, l have found that very satisfactory results can be obtained if the screen is inclined slightly downwardly at an angle of approximately as it extends in the direction of the arrow indicated at A in FIG. 2, and if it is also inclined downwardly at a small angle of approximately 3 in the direction of the arrow indicated at B in FIG. 2.

The screen 58 extends along a curved path as it carries the finished parts from the area of the entrance ramp 46 to the opening in the centerpost 24. One important advantage of providing such a curved path is that it increases the effective length of the screen and thereby increases the effective screening area so as to assure that all of the polishing media will have an opportunity to fall through the screen before reaching the centerpost opening 32. The outer and inner guide walls 40 and 42 also assist the separation of the parts and media. Such parts and media will impinge against the outer retaining wall 40 and to a somewhat lesser extent against the inner retaining wall 42 which impart additional action to assist in causing the media to be screened out. Such action is also useful in upsetting the finished parts so that all of the media will be removed from any cavities formed in such parts.

It is quite advantageous to eject the finished parts down through the bowl centerpost 24. As previously noted, the centerpost 24 is of a substantially reduced height compared to the outer bowl wall 22, and the screen 38 is disposed at approximately the same height as the centerpost, with the result that once the parts fall on the entrance portion of the screen 58'no further elevation of the parts is necessary in order to cause their ejection down through centerpost opening 32.

While the screen assembly 38 disclosed herein is of a type which requires that it be manually removed from the bowl 18 during a finishing operation, it will be understood that the screen may be designed so that it can simply be pivoted upwardly to an inoperative position during a finishing operation without completely removing the screen assembly, and if, desired, automatic actuating mechanism may be provided for moving the screen between its operative and inoperative positions.

I claim:

1. In a finishing machine of the type wherein polishing media and parts to be finished are mixed together in a container which is subjected to vibratory motion, the improvement comprising, in combination, springmounted bowl means having an outer wall which is generally circular in top plan and having a centerpost thereby defining between said outer wall and said centerpost an annular bowl chamber in which polishing media and parts to be finished are contained, vibratory drive means for imparting vibratory motion to said bowl causing the media and parts therein to move in a generally spiral path in a 360 traverse around said bowl chamber during a finishing operation, a discharge opening formed in said centerpost for discharging finished parts, and screen assembly means operatively positioned in said bow] at the completion of a finishing operation, said screen assembly including a screen disposed insaid bowl chamber at a height below that which the media and parts reach during their vibratory movement along said spiral path, said screen leading from said bowl chamber to said discharge opening whereby as media and parts move in a generally spiral path around said bowl chamber they pass over and onto said screen which is of a mesh to permit the polishing media to fall therethrough and remain in said bow] chamber while conducting the finished parts to the discharge opening in said centerpost.

2. A finishing machine as defined in claim 1 wherein said centerpost is of substantially reduced height relative to the height of said outer wall of said bowl means.

3. A finishing machine as defined in claim 1 wherein said screen is approximately coplanar.

4. A finishing machine as defined in claim 1 wherein said screen is operatively positioned in said bowl chamber at a height approximately equal to the height of said centerpost and wherein said screen is disposed in an approximately horizontal position.

5. A finishing machine as defined in claim 1 including removable plug means for closing the discharge opening in said centerpost during a finishing operation.

6. A finishing machine as defined in claim I where said screen as viewed in top plan defines a curved path leading from said bowl chamber to the discharge opening in said centerpost thereby increasing the effective length of said screen, said path extending partially around the circumference of said centerpost.

7. A finishing machine as defined in claim 6 wherein said screen assembly includes a curved guide wall positioned along the outer edge of said screen for the purpose of guiding finished parts along the curved path defined by said screen from said bowl chamber to the discharge opening in said centerpost.

8. A finishing machine as defined in claim 1 where viewed in vertical section said annular bowl chamber comprises a generally semi-circular bottom portion including an inner wall the upper end of which terminates approximately at the height of the centerpoint of said semi-circular bottom portion and an outer wall which extends upwardly substantially above said centerpoint, said inner wall comprising said bowl centerpost.

9. A finishing machine as defined in claim 1 including a plurality of headed lock pins projecting upwardly from said centerpost and a plurality of corresponding arcuate slots formed in said screen assembly whereby said screen assembly is removably locked to said bowl means by lowering said screen assembly onto said bowl means with said headed pins extending up through corresponding ones of said slots and by then rotating said screen assembly to a locked position, the direction of rotation for locking said parts and media as the latter move in a 360 traverse around said bowl chamber.

10. A finishing machine as defined in claim 8 where said screen is disposed at a height approximately equal to the height of said centerpoint and therefore at a height approximately equal to the height of said bowl centerpost.

11. A finishing machine as defined in claim 6 where said screen has an entrance portion positioned in said bowl chamber facing in a direction generally opposite to the direction of movement of the parts and media as the latter move in a 360 traverse around said bowl chamber, and where said screen extends around at least approximately one-third of the circumference of said centerpost.

12. In a finishing machine of the type wherein polishing media and parts to be finished are mixed together in a container which is subjected to vibratory motion, the improvement comprising, in combination, springmounted bowl means having an outer wall which is generally circular in top plan and having a centerpost thereby defining between said outer wall and said centerpost an annular bowl chamber in which polishing media and parts to be finished are contained, said centerpost being of substantially reduced height relative to the height of said outer wall, vibratory drive means for imparting vibratory motion to said bowl causing the media and parts therein to move in a generally spiral path in a 360 traverse around said bowl chamber during a finishing operation, a discharge opening formed in said centerpost for discharging finished parts, and screen assembly means operatively positioned in said bowl at the completion of a finishing operation, said screen assembly including an approximately coplanar screen disposed in said bowl chamber at a height below that which the media and parts reach during their vibratory movement along said spiral path, the height of said screen being approximately equal to the height of said centerpost with said screen disposed in an approximately horizontal position, and said screen leading from said bowl chamber to said discharge opening whereby as media and parts move in a generally spiral path around said bowl chamber they pass over and onto said screen which is of a mesh to permit the polishing media to fall therethrough and remain in said bowl chamber while conducting the finished parts to the discharge opening in said centerpost, and removable plug means for closing said discharge opening during a finishing operation.

13. A finishing machine as defined in claim 12 where said screen as viewed in top plan defines a curved path leading from said bowl chamber to the discharge opening in said centerpost, said screen having an entrance portion positioned in said bowl chamber facing in a direction generally opposite to the direction of movement of the parts and media as the latter move in a 360traverse around said bowl chamber, and where said screen extends around at least approximately onethird of the circumference of said centerpost thereby increasing the effective length of said screen.

14. A finishing machine as defined in claim 13 wherein said screen assembly includes a curved guide wall positioned along the outer edge of said screen for the purpose of guiding finished parts along the curved path defined by said screen from said bowl chamber to the discharge opening in said centerpost.

15. In a finishing machine of the type wherein polishing media and parts to be finished are mixed together in a container which is subjected to vibratory motion, the improvement comprising, in combination, springmounted bowl means having an outer wall which is generally circular in top plan and having a centerpost thereby defining between said outer wall and said centerpost an annular bowl chamber in which polishing media and parts to be finished are contained, and vibratory drive means for imparting vibratory motion to said bowl causing the media and parts therein to move in a generally spiral path in a 360 traverse around said bowl chamber during a finishing operation, said drive eans inc din a drive sh ft ousin su ended eneath sai spr mg-mounted owPmean an rigidly interconnected therewith, a drive shaft mounted in said housing for rotation about a vertical axis, a pair of radial arms connected to said drive shaft for rotation therewith, said radial arms being vertically spaced from one another and each carrying a weight thereon, a pair of vertically spaced eccentric bushings mounted on said drive shaft for rotation therewith, said bushings being mounted for rotation in corresponding bearings carried by said drive shaft housing, the vertical centerline of said bearings being offset from the vertical centerline of said drive shaft by an amount equal to the eccentricity of said bushings, a drive motor mounted on a stationary support independent of said drive shaft housing, a motor pulley and a drive shaft pulley, and endless belt means interconnecting the two pulleys for con necting said drive motor with said drive shaft for rotating the latter.

16. A finishing machine as defined in claim 15 where at least one of said two pulleys is adjustable for varying the speed at which said drive shaft is rotated.

PO-1O5O UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIQN Patent No. 3,693,298 Dated September 26, 1972 Inventor) Achille K. Ferrara It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

' Column 1, line 31, "cordless" should read --endless-- Column 5, line 58, "oscillator" should read -oscillatory- Column 6, line 31, "reduces" should read -reduced-- Column 7, line 37, insert --thebetween "through" and "centerpost" 7 Claim 9 (column 8, line 53) insert after "said" and before "parts" the following: -screen assembly being the same as the direction of movement of said-- Signed and sealed this 27th day of March 1973.

(SEAL) Attest:

EDWARD M. FLETCHER,JR. 7 ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. In a finishing machine of the type wherein polishing media and parts to be finished are mixed together in a container which is subjected to vibratory motion, the improvement comprising, in combination, spring-mounted bowl means having an outer wall which is generally circular in top plan and having a centerpost thereby defining between said outer wall and said centerpost an annular bowl chamber in which polishing media and parts to be finished are contained, vibratory drive means for imparting vibratory motion to said bowl causing the media and parts therein to move in a generally spiral path in a 360* traverse around said bowl chamber during a finishing operation, a discharge opening formed in said centerpost for discharging finished parts, and screen assembly means operatively positioned in said bowl at the completion of a finishing operation, said screen assembly including a screen disposed in said bowl chamber at a height below that which the media and parts reach during their vibratory movement along said spiral path, said screen leading from said bowl chamber to said discharge opening whereby as media and parts move in a generally spiral path around said bowl chamber they pass over and onto said screen which is of a mesh to permit the polishing media to fall therethrough and remain in said bowl chamber while conducting the finished parts to the discharge opening in said centerpost.
 2. A finishing machine as defined in claim 1 wherein said centerpost is of substantially reduced height relative to the height of said outer wall of said bowl means.
 3. A finishing machine as defined in claim 1 wherein said screen is approximately coplanar.
 4. A finishing machine as defined in claim 1 wherein said screen is operatively positioned in said bowl chamber at a height approximately equal to the height of said centerpost and wherein said screen is disposed in an approximately horizontal position.
 5. A finishing machine as defined in claim 1 including removable plug means for closing the discharge opening in said centerpost during a finishing operation.
 6. A finishing machine as defined in claim 1 where said screen as viewed in top plan defines a curved path leading from said bowl chamber to the discharge opening in said centerpost thereby increasing the effective length of said screen, said path extending partially around the circumference of said centerpost.
 7. A finishing machine as defined in claim 6 wherein said screen assembly includes a curved guide wall positioned along the outer edge of said screen for the purpose of guiding finished parts along the curved path defined by said screen from said bowl chamber to the discharge opening in said centerpost.
 8. A finishing machine as defined in claim 1 where viewed in vertical section said annular bowl chamber comprises a generally semi-circular bottom portion including an inner wall the upper end of which terminates approximately at the height of the centerpoint of said semi-circular bottom portion and an outer wall which extends upwardly substantially above said centerpoint, said inner wall comprising said bowl centerpost.
 9. A finishing machine as defined in claim 1 including a plurality of headed lock pins projecting upwardly from said centerpost and a plurality of corresponding arcuate slots formed in said screen assembly whereby said screen assembly is removably locked to said bowl means by lowering said screen assembly onto said bowl means with said headed pins extending up through corresponding ones of said slots and by then rotating said screen assembly to a locked position, the direction of rotation for locking said parts and media as the latter move in a 360* traverse around said bowl chamber.
 10. A finishing machine as defined in claim 8 where said screen is disposed at a height approximately equal to the height of said centerpoint and therefore at a height approximately equal to the height of said bowl centerpost.
 11. A finishing machine as defined in claim 6 where said screen has an entrance portion positioned in said bowl chamber facing in a direction generally opposite to the direction of movement of the parts and media as the latter move in a 360* traverse around said bowl chamber, and where said screen extends around at least approximately one-third of the circumference of said centerpost.
 12. In a finishing machine of the type wherein polishing media and parts to be finished are mixed together in a container which is subjected to vibratory motion, the improvement comprising, in combination, spring-mounted bowl means having an outer walL which is generally circular in top plan and having a centerpost thereby defining between said outer wall and said centerpost an annular bowl chamber in which polishing media and parts to be finished are contained, said centerpost being of substantially reduced height relative to the height of said outer wall, vibratory drive means for imparting vibratory motion to said bowl causing the media and parts therein to move in a generally spiral path in a 360* traverse around said bowl chamber during a finishing operation, a discharge opening formed in said centerpost for discharging finished parts, and screen assembly means operatively positioned in said bowl at the completion of a finishing operation, said screen assembly including an approximately coplanar screen disposed in said bowl chamber at a height below that which the media and parts reach during their vibratory movement along said spiral path, the height of said screen being approximately equal to the height of said centerpost with said screen disposed in an approximately horizontal position, and said screen leading from said bowl chamber to said discharge opening whereby as media and parts move in a generally spiral path around said bowl chamber they pass over and onto said screen which is of a mesh to permit the polishing media to fall therethrough and remain in said bowl chamber while conducting the finished parts to the discharge opening in said centerpost, and removable plug means for closing said discharge opening during a finishing operation.
 13. A finishing machine as defined in claim 12 where said screen as viewed in top plan defines a curved path leading from said bowl chamber to the discharge opening in said centerpost, said screen having an entrance portion positioned in said bowl chamber facing in a direction generally opposite to the direction of movement of the parts and media as the latter move in a 360*traverse around said bowl chamber, and where said screen extends around at least approximately one-third of the circumference of said centerpost thereby increasing the effective length of said screen.
 14. A finishing machine as defined in claim 13 wherein said screen assembly includes a curved guide wall positioned along the outer edge of said screen for the purpose of guiding finished parts along the curved path defined by said screen from said bowl chamber to the discharge opening in said centerpost.
 15. In a finishing machine of the type wherein polishing media and parts to be finished are mixed together in a container which is subjected to vibratory motion, the improvement comprising, in combination, spring-mounted bowl means having an outer wall which is generally circular in top plan and having a centerpost thereby defining between said outer wall and said centerpost an annular bowl chamber in which polishing media and parts to be finished are contained, and vibratory drive means for imparting vibratory motion to said bowl causing the media and parts therein to move in a generally spiral path in a 360* traverse around said bowl chamber during a finishing operation, said drive means including a drive shaft housing suspended beneath said spring-mounted bowl means and rigidly interconnected therewith, a drive shaft mounted in said housing for rotation about a vertical axis, a pair of radial arms connected to said drive shaft for rotation therewith, said radial arms being vertically spaced from one another and each carrying a weight thereon, a pair of vertically spaced eccentric bushings mounted on said drive shaft for rotation therewith, said bushings being mounted for rotation in corresponding bearings carried by said drive shaft housing, the vertical centerline of said bearings being offset from the vertical centerline of said drive shaft by an amount equal to the eccentricity of said bushings, a drive motor mounted on a stationary support independent of said drive shaft housing, a motor pulley and a drive shaft pulley, and endless belt means interconnecting the two Pulleys for connecting said drive motor with said drive shaft for rotating the latter.
 16. A finishing machine as defined in claim 15 where at least one of said two pulleys is adjustable for varying the speed at which said drive shaft is rotated. 